A method for constructing a system suitable for the specifications of a client by connecting each of a plurality of processors to associated memory devices with switches has been proposed, for example, in Japanese Laid-open Patent Publication No. 2004-240697. In this type of system, during a period in which programs are not used frequently, a plurality of programs distributed over a plurality of memory devices are moved to one memory device, thereby reducing power consumption. An example of this technique is disclosed in Japanese Laid-open Patent Publication No. 2010-97533.
The following sound recording apparatus is disclosed in, for example, Japanese National Publication of International Patent Application No. 2003-504673. Musical sound generated in a musical instrument is recorded in a sound recording apparatus per predetermined unit time, thereby making it possible to search for musical sound. When the sound recording apparatus is full of digital information, recorded digital information is overwritten with new digital information.
The following technique has been proposed in, for example, International Publication Pamphlet No. WO2005/3951. Redundant data items are stored in different memory devices, and when an abnormality of a memory device has been detected, a redundant data item stored in a memory device is copied into a newly assigned memory device. The following method has also been proposed in, for example, Japanese Laid-open Patent Publication No. 2006-260376. Data is stored in a master disc and a backup disc, and when a failure of the master disc has been detected, data stored in the backup disc is copied into an alternative area of the master disc.
In the above-described system, a plurality of memory devices are connected to a processor with switches, and the processor writes data into one of the memory devices connected to the processor via the switches. That is, a memory device into which data will not be written and a memory device into which data has already been written are also connected to the processor via the switches. Accordingly, when the processor writes data into one memory device, the performance in writing data may be decreased due to the interference of other memory devices connected to the processor via the switches.